Carboxylic acid ester bleach activators are known. U.K. Pat. No. 864,798, Hampson et al (Apr. 6, 1961), discloses bleaching compositions comprising an inorganic persalt and an organic ester of an aliphatic carboxylic acid wherein the size of the carboxylic acid ester particles are such that at least 70% of them are retained on a 60 mesh British Standard sieve. It is preferred that the ester be derived from an aliphatic carboxylic acid having not more than 10, preferably less than 8 carbon atoms. The proportion of molecules of reactive ester to each atom of available oxygen in the persalt is from 1/4 to 4 and preferably from 1/2 to 1.5. It is stated that such bleaching compositions are stable during storage.
U.K. Pat. No. 836,988, Davies et al (June 9, 1960), discloses bleaching compositions containing hydrogen peroxide or inorganic persalt and organic carboxylic esters. A test is described to define the esters within the invention. The molecules of ester per one atom of available oxygen are from 1/4 to 2 and particularly from 1/2 to 1.5. It is stated that such esters provide improved bleaching at temperatures from 50.degree. C. to 60.degree. C. relative to that obtained with the persalt alone.
It is also known that the bleach activators that are believed to exhibit surface activity that are utilized in combination with peroxygen bleaches provide particularly effective surface bleaching. U.S. Pat. No. 4,283,301, Diehl (Aug. 11, 1981), discloses bleaching compositions comprising a peroxygen bleach and a bleach activator of the general formula: ##STR1## wherein R is an alkyl chain containing from about 5 to about 13 carbon atoms, R.sup.2 is an alkyl chain containing from about 4 to about 24 carbon atoms and each Z is a leaving group as defined therein. It is preferred that such bleaches and bleach activators are present in equimolar ratios.